1. Field of the Invention
The present invention is related to the field of seismic activity detectors, or more generally, to earthquake detectors. More specifically, the invention relates to earthquake detectors that provide a light and an audio alarm upon sensing an occurrence of an earthquake.
2. Description of Related Art
Low level seismic activity or earthquakes are constantly occurring over the surface of the earth and generally go unnoticed by most people during its occurrence. However, higher level earthquakes can be readily felt and powerful earthquakes can cause significant destruction to property as well as human injury or death. Geologists and seismologists in general, have not been able to accurately predict the location, magnitude and times of earthquakes. Thus, in most cases, the occurrence of an earthquake is sudden and unexpected. While tremors will last at most for only a few minutes, most of the major destruction, injury and death will occur within ten seconds following the initial impact of the first tremor. As can be expected, earthquakes instill fear and panic in many people because of their known dangers and because they are beyond human control. In this regard, various detectors have been created to provide an alarm when an earthquake is sensed so that people can quickly recognize the occurrence of the earthquake and to escape from harms way such as falling objects, glass, etc. Examples of such detectors are illustrated in U.S. Pat. No. 4,262,289 to Rivera, U.S. Pat. No. 4,297,690 to Baker and U.S. Pat. No. 4,689,997 to Windisch. However, various limitations have been found in such detectors that limit their utility and effectiveness. For instance, many of these detectors use a pendulum to detect the earthquake and to trigger an alarm when the pendulum is swung laterally by the movement of the earth to contact a ring shaped contact. Such simplistic designs have been found to be inadequate however, since there are no provisions made to detect movement of the earth in the vertical direction. Thus, such designs do not provide the level of sensitivity required to quickly and accurately sense the different movements of the earth. The detector in Windisch sought to remedy the lack of sensitivity by providing a motion detector which will detect vertical movement of the earth as well as the lateral movement. Whereas sensitivity was improved, sensitivity adjustment of the detector in Windisch is not possible thereby undermining some of its advantages.
In addition, all these detectors have other limitations which limit their utility and effectiveness. For instance, it is noted that many earthquakes occur during the night when people are asleep. When awaken by the shaking caused by the earthquake, the person is initially confused and does not know why he or she awoke and may go back to sleep. This confusion and state of grogginess can cause potentially hazardous behavior such as walking near glass or other areas of the room in which the person may be injured. Whereas the above discussed alarms provide a loud sound enough to quickly awaken a person in its proximate area and to inform the person the occurrence of earthquake, when such earthquakes occurs at night, the darkness of the surroundings poses additional element of danger to the person. As individuals fully awaken, fear and panic is instilled as they realize that they are in an earthquake and are in danger. However, when confused and in a panic state, it is often difficult for a person to search for a light or lamp switch which will allow them to see in order to escape from harms way without being endangered by falling objects and/or tripping over household items within the room.
To provide illumination in such situations, various detectors have been made that activate an alarm while providing a safety lamp upon detecting an earthquake. Such a detector having an alarm and light is illustrated in U.S. Pat. No. 5,418,523 to Anderson et al. which uses a pendulum and a ring shaped contact to sense lateral movement of the earth. Upon detecting an earthquake, the detector in Anderson provides an alarm and a floodlamp. However, the sensitivity limitations of some of the previously discussed detectors is also present in this detector since it cannot detect the vertical movements of the earth. To increase sensitivity, European Patent No. 161 378 discloses a similar detector in which a pendulum is levered on a spring contact to allow the pendulum to be moved in a vertical direction to detect vertical movement of the earth. Despite these additional features, this detector, as well as the other detectors, have various limitations which limit their utility and effectiveness.
In particular, whereas the detector disclosed in the European Patent No. 161 378 is capable of detecting vertical and lateral movement of the earth during an earthquake and further provides a light as well as an alarm, like the detector in Windisch, the vertical sensitivity is also not adjustable. Moreover, the manufacturing of the detector has been found to be difficult because of the complexity of providing a pendulum which is levered on a spring contact. Because the vertical sensitivity is not adjustable, the spring contact had to be manufactured with high degree of precision to provide just the right amount of spring preload to center the lever in the levered spring contact. This adds to the cost of the earthquake detector while diminishing its reliability.
Moreover, all of the prior art earthquake detectors fail to provide any utility beyond the proximate area at which the detector is mounted. These earthquake detectors are generally fixedly mounted on a wall or another surface and in the case of the detectors with a light, facilitate the evacuation of the room in which the detector is mounted. However, larger earthquakes can cause electrical lines to be damaged thereby rendering lights and lamps within the house as well as those in the neighborhood totally useless. Of course, such power failure can pose additional danger to a person seeking to escape harms way caused by the earthquake. These additional dangers include falling down stairs and being injured by falling objects and debris, etc. The prior art earthquake detecting alarm devices fail to provide any utility and assistance to the user in such cases once the person leaves the proximate area where the detector is mounted.
Therefore, there exists a need for an improved earthquake detector with a light and an alarm feature which will provide aid in the evacuation of the room in which the detector is mounted. There also exists a need for such a detector with heightened sensitivity which can detect vertical movement of the earth in a simple and cost effective manner. There also exists a need for an earthquake detector where the sensitivity of the detector can be easily adjusted. Furthermore, there also exists a need for such a detector which can provide utility and assistance to the user beyond the proximate area where the detector is mounted.